By the time he was 12 years old, sculptor and stone carver Walter S. Arnold had already picked up a chisel and decided on his future profession.

He decided this despite being told that no one knew how to make his favorite stone carvings, gargoyles, anymore and that creating them was a lost art. So it should be all the more gratifying for anyone exploring Arnold's upcoming exhibit — opening July 9 at The Kalo Foundation of Park Ridge — that gargoyles are prominently featured among a wide range of his other works.

"I had already fallen in love with them at that age," said Arnold, who started making a specialty of gargoyles when he returned from several years of apprenticeship in Italy and became a stone carver at the Washington National Cathedral in D.C., working with a fifth-generation Italian stone carver.

In fact, Arnold was so sure about the work he intended to do that he applied at the age of 16 for a similar position at the Washington National Cathedral. He had a few years of high school to finish first, however, before arranging an early transfer to the University of Illinois at Chicago, taking all the art history courses he could until he turned 18 "and was out of there." Soon after that, he was training as an apprentice under master stone carvers in Italy, working in marble.

"At one shop I was working with two men who, between them, had 110 years of experience," said Arnold, who trained in styles ranging from classical and Renaissance to gothic, Baroque and Arts and Crafts among others. "I learned by connecting with people from long traditions who had learned from their predecessors. The continuing tradition is very important to me."

It's important to others as well, since the only way to learn stone carving is through apprenticeship. Arnold, a proud member of the Journeyman Stone Cutters Association, the oldest trade union in America, points out that there were roughly 1,000 stone carvers working in Chicago in 1900, but now there are only 60 to 100 nationwide.

Arnold recalls that while he was working at Washington National Cathedral, a man in his late 80s stopped by to talk and told him he worked on the cathedral decades before — and had his first job in the 1920s working on the Tribune Tower. After watching Arnold work, the man invited him to his home and gave him all his tools "because he wanted his tools to stay alive."

Soon after that, when Arnold moved back to Chicago in 1985 and opened his own shop, one of his first jobs was repairing stone carvings on the Tribune Tower and he used the old man's tools to do it.

While the number of people who have mastered stone carving is nowhere near what it once was, Arnold believes stone carving and sculpture will always be viable because its appeal is both ancient and universal.

"It's such a basic, solid, permanent material. Stone is a very simple building block of nature, but it's also something we know will last," he said. "It's a small number, compared to what it once was, but a few of us are dedicated to doing it and doing it right."